From fb29f5b0fb77e2079d4b272a932c15bf355ffb65 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Axel=20D=C3=B6rfler?= <axeld@pinc-software.de>
Date: Thu, 4 Jan 2007 14:25:13 +0000
Subject: [PATCH] Changes to let updates happen less frequently: *
 _ContrainPoint() was broken as it could never change the point it was
 supposed   to contrain. * MouseDown() no longer sends a notification message
 automatically (only if it   changed something) * MouseMoved() and synchronous
 MouseDown() will now only send modification messages   if something actually
 changed (not for every mouse update). * After key presses, the invokation
 message is only sent when the value changed.

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@19697 a95241bf-73f2-0310-859d-f6bbb57e9c96
---
 headers/os/interface/Slider.h |  2 +-
 src/kits/interface/Slider.cpp | 34 ++++++++++++++++++++++++++--------
 2 files changed, 27 insertions(+), 9 deletions(-)

diff --git a/headers/os/interface/Slider.h b/headers/os/interface/Slider.h
index eb1e6f0327..e0666d9b33 100644
--- a/headers/os/interface/Slider.h
+++ b/headers/os/interface/Slider.h
@@ -148,7 +148,7 @@ class BSlider : public BControl {
 
 				float		_MinPosition() const;
 				float		_MaxPosition() const;
-				bool		_ConstrainPoint(BPoint point, BPoint compare) const;
+				bool		_ConstrainPoint(BPoint& point, BPoint compare) const;
 
 		virtual	void		_ReservedSlider5();
 		virtual	void		_ReservedSlider6();
diff --git a/src/kits/interface/Slider.cpp b/src/kits/interface/Slider.cpp
index 99baf89148..5a3c7d5866 100644
--- a/src/kits/interface/Slider.cpp
+++ b/src/kits/interface/Slider.cpp
@@ -407,14 +407,20 @@ BSlider::KeyDown(const char *bytes, int32 numBytes)
 	switch (bytes[0]) {
 		case B_LEFT_ARROW:
 		case B_DOWN_ARROW: {
+			int32 oldValue = Value();
+
 			SetValue(Value() - KeyIncrementValue());
-			Invoke();
+			if (oldValue != Value())
+				Invoke();
 			break;
 		}
 		case B_RIGHT_ARROW:
 		case B_UP_ARROW: {
+			int32 oldValue = Value();
+
 			SetValue(Value() + KeyIncrementValue());
-			Invoke();
+			if (oldValue != Value())
+				Invoke();
 			break;
 		}
 		default:
@@ -423,8 +429,13 @@ BSlider::KeyDown(const char *bytes, int32 numBytes)
 }
 
 
+/*!
+	Makes sure the \a point is within valid bounds.
+	Returns \c true if the relevant coordinate (depending on the orientation
+	of the slider) differs from \a comparePoint.
+*/
 bool
-BSlider::_ConstrainPoint(BPoint point, BPoint comparePoint) const
+BSlider::_ConstrainPoint(BPoint& point, BPoint comparePoint) const
 {
 	if (fOrientation == B_HORIZONTAL) {
 		if (point.x != comparePoint.x) {
@@ -465,7 +476,8 @@ BSlider::MouseDown(BPoint point)
 	_ConstrainPoint(point, fInitialLocation);
 	SetValue(ValueForPoint(point));
 
-	InvokeNotify(ModificationMessage(), B_CONTROL_MODIFIED);
+	if (_Location() != fInitialLocation)
+		InvokeNotify(ModificationMessage(), B_CONTROL_MODIFIED);
 
 	if (Window()->Flags() & B_ASYNCHRONOUS_CONTROLS) {
 		SetTracking(true);
@@ -481,8 +493,11 @@ BSlider::MouseDown(BPoint point)
 			GetMouse(&point, &buttons, true);
 
 			if (_ConstrainPoint(point, prevPoint)) {
-				SetValue(ValueForPoint(point));
-				InvokeNotify(ModificationMessage(), B_CONTROL_MODIFIED);
+				int32 value = ValueForPoint(point);
+				if (value != Value()) {
+					SetValue(value);
+					InvokeNotify(ModificationMessage(), B_CONTROL_MODIFIED);
+				}
 			}
 		}
 		if (_Location() != fInitialLocation)
@@ -509,8 +524,11 @@ BSlider::MouseMoved(BPoint point, uint32 transit, const BMessage *message)
 {
 	if (IsTracking()) {
 		if (_ConstrainPoint(point, _Location())) {
-			SetValue(ValueForPoint(point));
-			InvokeNotify(ModificationMessage(), B_CONTROL_MODIFIED);
+			int32 value = ValueForPoint(point);
+			if (value != Value()) {
+				SetValue(value);
+				InvokeNotify(ModificationMessage(), B_CONTROL_MODIFIED);
+			}
 		}
 	} else
 		BControl::MouseMoved(point, transit, message);